﻿// Copyright 2006 - Ricardo Stuven (rstuven@gmail.com)
//
// This file is part of MsSqlSpatial.
// MsSqlSpatial is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// MsSqlSpatial is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public License
// along with MsSqlSpatial; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using GeoAPI.Geometries;
using MsSqlSpatial;

public partial class UserDefinedFunctions
{
	/// <summary> 
	/// Tests whether the distance from this <c>Geometry</c>
	/// to another is less than or equal to a specified value.
	/// </summary>
	/// <param name="geom">the Geometry to check the distance to.</param>
	/// <param name="distance">the distance value to compare.</param>
	/// <returns><c>true</c> if the geometries are less than <c>distance</c> apart.</returns>
	[SqlFunction(IsDeterministic = true)]
	public static SqlBoolean IsWithinDistance(SqlBytes ewkb1, SqlBytes ewkb2, SqlDouble distance)
	{
		IGeometry geometry1 = ConvertGeometry.ToGeometry(ewkb1);
		if (geometry1 != null && !distance.IsNull)
		{
			IGeometry geometry2 = ConvertGeometry.ToGeometry(ewkb2);
			if (geometry2 != null)
			{
				if (geometry1.SRID != geometry2.SRID)
					throw new DifferentSridException(geometry1.SRID, geometry2.SRID);
				return new SqlBoolean(geometry1.IsWithinDistance(geometry2, distance.Value));
			}
		}
		return SqlBoolean.Null;
	}
};


